I'm looking at my air filter for the first time and it looks a little dirty. I started searching the archives here for a replacement part and came across the UNI-Foam conversion and was wondering who has done it, and if they noticed any change in performance, did oil get dirty quicker, etc .

I've read a couple different ways to do it. 1. Cut a piece the size of the airbox or 2. rebuild the stock filter with UNI-Foam using the original filter core. I'm leaning towards the second approach, but would appreciate all input.